The Optimum Design for a Rotating Shaft Supported by Journal Bearings : 3rd Report, Nomalization of the Reference Function and Consideration of uncertainty of design constants

Abstract

It is useful for the optimum design of journal bearings if each element of the reference function is weighed easily and quantitatively. This paper proposes a method to normalize the reference function for the optimum design of the journal bearings of a rotor-bearing system. Next, this paper presents a method for the stochastic optimum design of journal bearings. In this case, the chance-constraint technique is adopted to design the journal bearing considering reliability, in which the constraints and the reference function are treated as random variables. In numerical examples, design variables with errors in the design stage are considered and an optimum solution is obtained by the stochastic approach. This shows that the reliability of the optimum solution obtained by the deterministic approach is low since it is nearly always on the boundary values. And it is also known that the feasible region varies depending on the variance of design constants.